I agree with pparks1, Almost anytime you change the clock speed the computer has to shut completey down to readjust. But, just like him, I don't know what would be making noise. It has to be some component in the computer because I don't know of anything in the motherboard that would make noise.

I also agree that the difference in clock speed would probably make very little if any noticable difference. You can gain about as much by running it at 1333 and lowering the timings slightly. Instead of 7-7-7 try thr ram at 1333 6-7-6. If it would run like that, it would be about the same as 1600.